1. Field of the Invention
This invention relates to apparatus for applying surgical clips to body tissue. More particularly, the invention relates to apparatus having a self-contained supply of surgical clips and constructed to apply those clips, one at a time, through relative movement of the thumb and fingers of one hand.
2. Description of the Prior Art
Surgical clips, also known as hemostatic clips, serve to seal or clamp off blood vessels or other sections of tissue which are cut during surgical procedures. Each clip has two coplanar arms which surround the tissue to be clamped. The clip applying instrument holds these arms while the clip is positioned about the tissue to be clamped and then brings the arms toward each other, in their common plane, to seal off the tissue.
A surgeon may apply twenty or more clips during the course of an operation. Early commercial instruments held one clip at a time, which a surgical assistant inserted in the instrument from a clip dispenser prior to each use. These instruments were generally of the scissor or plier variety in which the clip was held in jaws at the distal end of two pivoted lever arms. To handle the stresses encountered in closing the clip, these lever arms had to be of high beam strength. Use of high beam strength, surgical instrument grade materials increased the cost of these instruments so that they were sold as permanent instruments, and only the clip dispenser was disposable.
More recently, a disposable instrument, incorporating the clip dispenser as part of the instrument, has come into general use. This instrument is shown generally in U.S. Pat. Nos. 4,152,920 and 4,242,902, assigned to the assignee of this invention. It employs a movable clip cartridge mounted on the instrument. Clips are loaded into the jaws of the instrument through a pumping action in which the cartridge is slid forward and then backward over the jaws. As such, the instrument requires two hands to load a clip: one to move the cartridge and the other to hold the instrument. In many cases, this means that two people become involved in applying clips, as was the case with the separate dispenser instruments, since the surgeon's hand which is not holding the instrument, and thus theoretically could be used to move the cartridge, often is needed to hold the tissue being clamped in the proper orientation. On such occasions, the surgeon will present the instrument to an assistant, and the assistant will pump the cartridge to load a clip.
To close a clip, this instrument, rather than using pivoted levers, surrounds the jaws and their supporting arms with a sleeve and closes the jaws by moving them back into the sleeve and camming them shut through contact with the distal end of the sleeve. Because of the construction of the movable cartridge, this instrument is generally limited to the application of relatively small clips.
Instruments for applying surgical clips through the use of only one hand have also been developed. For example, U.S. Pat. No. 4,166,466, assigned to the assignee of this invention, shows a lever closure instrument in which part of the movement of the levers is used to feed a clip to the instrument's jaw and the remainder of the movement is used to close the clip. Canadian Pat. No. 1,082,552 and European Patent Publication No. A1 0,000,756 show other one-handed instruments. All of these instruments are of the lever closure type and thus require strong, expensive materials.